Intermediate roller element for universal joint

ABSTRACT

An intermediate roller element for a universal joint includes a strip (12), one face of which includes at least one longitudinal roller track and balls (20) which roll along the track. The balls are held by a cage (22) produced in the form of a plate (24) which extends in a plane substantially parallel to the overall plane of the track (16), and includes cells in which the balls (20) are received. The cage includes portions (28, 32, 34) joining the cage (22) to the strip in order to form a unitary sub-assembly.

BACKGROUND OF THE INVENTION

The present invention relates to an intermediate roller element for auniversal joint.

The invention relates more particularly to a roller element for auniversal joint of the type described and represented in patent documentFR-A-2,580,751.

According to this design of a universal joint, termed a ball-typetriplane joint, recourse is made to an intermediate roller assembly,which is arranged between one arm of the tripod and a raceway formedopposite in the barrel of the joint, of the type including a sole-plateproduced in the form of a strip. One face includes at least onelongitudinal roller track and balls which roll along the track and whichare held by a cage produced in the form of a plate which extends in aplane substantially parallel to the overall plane of the track and whichincludes cells in which the balls are received.

This design of an intermediate roller assembly makes it possible toobtain satisfactory operation of the joint, but it makes assembly of thelatter particularly complicated, insofar as it is necessary to install agreat number of components. In particular, the strip, the balls and thecage make assembly operations particularly difficult to automate.

SUMMARY OF THE INVENTION

In order to overcome these drawbacks, the invention proposes anintermediate roller assembly of the type mentioned previously thatincludes a means for joining the cage to the strip in order toconstitute a unitary sub-assembly.

According to other characteristics of the invention, the cage includesat least two opposing lateral tabs, each of which extends from alongitudinal edge of the cage in the direction of the strip, and thefree ends of which each interact with a retaining surface formedopposite on the strip in order to limit the displacement of the cagewith respect to the strip in a direction perpendicular to each plate ofthe track. Each lateral tab extends along a lateral face of the stripand the free end of the strip interacts with a fastening face formedopposite on the said lateral face.

An intermediate roller element includes a means for limiting thedisplacements of the cage with respect to the strip in the longitudinalrolling direction of the balls. This means includes a stop piece formedon the track so that it projects and splits the track into two tracks,on each of which at least one ball rolls.

This means also includes at least one fixed stop piece formed on thestrip which is capable of interacting with at least one stop-piecesurface of the cage.

The strip includes, on at least one of its lateral faces, one projectingstop piece which is received with a clearance between two stop-piecesurfaces made up of the longitudinal end edges of a window formed in oneof the lateral tabs of the cage. The strip also includes, at least onone of its lateral faces, two projecting stop pieces which are arrangedrespectively in the vicinity of the opposing longitudinal ends of thislateral face, and between which stop pieces one of the two lateral tabsof the cage is received with a clearance. The lateral tabs of the caseare elastically deformable in order to allow the case to be installed onthe strip by elastically clipping it in. Each cell is shaped such as tojoin the balls to the unit sub-assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will emerge uponreading the detailed description which follows, for the understanding ofwhich reference will be made to the appended drawings, in which:

FIG. 1 is a lateral elevational view of a first embodiment of anintermediate roller element produced in accordance with the teachings ofthe invention;

FIG. 2 is a right-hand lateral view of the roller element illustrated inFIG. 1;

FIG. 3 is a sectional view taken on line 3--3 of FIG. 2;

FIG. 4 is a lateral elevational view of a second embodiment of anintermediate roller element produced in accordance with the teachings ofthe present invention;

FIG. 5 is a right-hand lateral view of the roller element illustrated inFIG. 4;

FIG. 6 is a sectional view taken on line 6--6 of FIG. 5;

FIG. 7 is a lateral elevational view of a third embodiment of anintermediate roller element produced in accordance with the teachings ofthe present invention;

FIG. 8 is a right-hand lateral view of the roller element illustrated inFIG. 7;

FIG. 9 is a sectional view taken on line 9--9 of FIG. 8;

FIG. 10 illustrates a variant of the shape of a roller track;

FIG. 11 illustrates a further variant of the shape of a roller track;and

FIG. 12 illustrates a yet further variant of a roller track according tothe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 3 represent an intermediate roller element 10 intended toequip a universal joint of the type described and represented indocument FR-A-2,580,751, the content of which reference may be made inorder to know the design and production details of a ball-type triplaneuniversal joint.

Each intermediate element 10 includes a sole-plate produced in the formof a strip of an overall elongate parallelepipedal shape.

A strip 12 includes, on its upper longitudinal face 14, a roller track16a which, in the embodiment illustrated in FIGS. 1 to 3 and 10, isdivided into two tracks 16A and 16B by a projecting intermediatepartition 18 which is arranged substantially in the middle of the strip12.

Each of the two tracks 16A, 16B receives a ball 20 that can rollthereon.

The two balls 20 are held by a cage 22, which is essentially made up ofa plate 24 substantially parallel to the plane of the upper longitudinalface 14 of the strip 12, and in which two cells 26 are formed, each oneof which receives a ball 20.

In this embodiment, each cell is produced partially in the form of adish 27 such that the balls are retained by the cage, that is to saythat cannot escape upwards when considering the figures.

In accordance with the teachings of the invention, the plate 24 isextended, on either side of the strip 12, by two lateral tabs 28 each ofwhich extends vertically downwards from the plate 24 along a lateralface 30 of the strip 12. The end 32 of each lateral tab 28 is slightlycurved in the direction of the median plane of symmetry P of theintermediate element 10 such as to constitute a retaining spur whichextends facing an inclined surface portion 34, formed at the lower partof the strip in an extension of the vertical planar part of the lateralface 30. The lateral faces 30 are received with a slight clearance withthe internal faces opposite the lateral tabs 28 such as not to detractfrom the rolling capability of the balls 20 along the tracks 16A and16B.

The interaction of the ends 32 with the inclined surfaces 34 preventsthe cage 22 and the balls 20 from detaching from the strip 12 in adirection perpendicular to the plane of the upper face 14. Theintermediate element 10 thus constitutes a unit sub-assembly which canbe assembled independently of the joint and then installed when thejoint is assembled.

The choice of material of the cage 22 is such that the lateral tabs 28may be deformed elastically so as to allow the cage 22 with the balls 20to be installed on the strip 12 by elastically clipping it on from thetop downwards when considering the figures.

The displacements of the case 22 and of the balls 20 with respect to thestrip 12 are also limited in the direction of rolling of the balls bythe central projection 18, against which one or the other of the balls20 can come into abutment.

In the variant illustrated in FIG. 10, the tracks 16A and 16B areslightly inclined so as to allow automatic recentering of the cage 22with respect to the strip 12 when the joint is in operation.

In the second embodiment illustrated in FIGS. 4 to 6 and 11, a rollertrack 16a is a continuous straight track.

A means for limiting the displacement of the cage 22a with respect to astrip 12a in the longitudinal rolling direction of the balls is made upof at least one stop piece 36, which is formed on at least one lateralface 30 of the strip 12a so that it projects. It is received with aclearance between vertical edges 38 of the cage 22, which longitudinallydefine a window 40 formed in the lateral tab 28a of the cage 22a.

In order to simplify the assembly of the intermediate roller element 10and make use of symmetrical components, projecting stop pieces 36 arepreferably arranged symmetrically on each of the lateral faces 30 of thestrip 12a, and they are each received in a window 40 in correspondinglateral tabs 28a of the cage 22a.

In the embodiment illustrated in FIG. 11, a track 16a includes twoinclined lengths 16Aa and 16Ba which provide automatic recentering ofthe cage 22 with respect to the strip 12 when the joint is in operation.

In the third embodiment illustrated in FIGS. 7 to 9, the means forlimiting the displacement of a cage 22b with respect to a strip 12b inthe longitudinal rolling direction of the balls is made up of twolongitudinal stop pieces 40 arranged respectively in the vicinity oftransverse end faces 42 of the strip 12b. They are formed on the lateralfaces 30 so that they project.

Each lateral tab 28b of the cage 22b possesses a reduced length withrespect to that of the tabs illustrated in FIGS. 1 to 4, such that it isreceived with a clearance between the stop pieces 40. Vertical end edges44 of the tabs 28b are thus capable of interacting with one or the otherof the stop pieces 40, depending on the displacement of the cage 22bwith respect to the strip 12b.

In the variant illustrated in FIG. 12, the roller track 16b includes twooppositely inclined lengths 16Ab and 16Bb which bring about automaticrecentering of the cage 22 with respect to the strip 12 when the jointis in operation.

We claim:
 1. An intermediate roller assembly, comprising:a strip havingone face which includes at least one roller track that extendslongitudinally of said strip; a plurality of roller elements in rollingcontact with said at least one track; and a cage comprising a plate thatgenerally extends in a plane that is substantially parallel to said atleast one roller, track and a plurality of cells in which said rollerelements are respectively received, said cage comprising meanscooperating with said strip for maintaining said roller elements on saidat least one track such that said strip, said roller elements and saidcage form a unitary assembly.
 2. The intermediate roller element ofclaim 1, wherein said means for maintaining comprises two opposinglateral tabs that extend from a longitudinal edge of said cage and havefree ends which interact with respective retaining surfaces formed onopposite sides of said strip so as to restrict movement of said cagerelative to said strip in a direction substantially perpendicular tosaid track.
 3. The intermediate roller element of claim 2, wherein saidtwo opposing lateral tabs extend along lateral faces of said strip, saidretaining surfaces being formed on said lateral faces opposite to saidlateral tabs.
 4. The intermediate roller element of claim 3, wherein atleast one of said cage and said strip further comprises a means forlimiting displacement of said cage with respect to said strip in thelongitudinal rolling direction of said roller elements in thelongitudinal direction of said strip.
 5. The intermediate roller elementof claim 4, wherein said means for limiting displacement of said cagewith respect to said strip in the longitudinal rolling direction of saidroller elements comprises a stop piece formed on said at least one trackthat projects outwardly of said at least one track and divides said atleast one track into two tracks, each of said tracks having at least onesaid roller element thereon.
 6. The intermediate roller element of claim1, wherein each of said plurality of cells has a shape which holds arespective one of said plurality of roller elements and maintains saidroller elements as part of said unit assembly.
 7. The intermediateroller element of claim 1, wherein said roller elements are balls.
 8. Anintermediate roller assembly, comprising:a strip having one face whichincludes at least one roller track that extends longitudinally of saidstrip; a plurality of roller elements in rolling contact with said atleast one track; a cage comprising a plate that generally extends in aplane that is substantially parallel to said at least one roller track,a plurality of cells in which said roller elements are respectivelyreceived, and means cooperating with said strip for maintaining saidroller elements on said at least one track such that said strip, saidroller elements and said cage form a unitary assembly; wherein saidmeans for maintaining comprises two opposing lateral tabs that extendfrom a longitudinal edge of said cage and have free ends which interactwith respective retaining surfaces formed on opposite sides of saidstrip so as to restrict movement of said cage relative to said strip ina direction substantially perpendicular to said track; wherein said twoopposing lateral tabs extend along lateral faces of said strip, saidretaining surfaces being formed on said lateral faces opposite to saidlateral tabs; wherein at least one of said cage and said strip furthercomprises a means for limiting displacement of said cage with respect tosaid strip in the longitudinal rolling direction of said roller elementsin the longitudinal direction of said strip; and wherein said means forlimiting displacement of said cage with respect to said strip in thelongitudinal rolling direction of said roller elements comprises atleast one fixed stop piece formed on said strip and at least one stopsurface on said cage, said fixed stop piece being capable of interactingwith said at least one stop surface.
 9. The intermediate roller elementof claim 8, wherein said at least one fixed stop piece comprises atleast one fixed projecting stop piece projecting from one of saidlateral faces of said strip, and said at least one stop surface on saidcage comprises two stop-piece surfaces forming longitudinal end edges ofa window formed in one of said lateral tabs of said cage.
 10. Theintermediate roller element of claim 8, wherein said strip has oppositelongitudinal ends on one of said lateral faces thereof, said at leastone fixed stop piece comprises stop pieces located at said oppositelongitudinal ends of said lateral face, and one of said lateral tabs ofsaid cage is received with a clearance between said stop pieces, said atleast one stop surface being formed on the one of said lateral tabs ofsaid cage.
 11. An intermediate roller assembly, comprising:a striphaving one face which includes at least one roller track that extendslongitudinally of said strip; a plurality of roller elements in rollingcontact with said at least one track; a cage comprising a plate thatgenerally extends in a plane that is substantially parallel to said atleast one roller track, a plurality of cells in which said rollerelements are respectively received, and means cooperating with saidstrip for maintaining said roller elements on said at least one tracksuch that said strip, said roller elements and said cage forms unitaryassembly; and wherein said means for maintaining comprises lateral tabson said cage that are elastically deformable such that said tabs can beelastically clipped on to said strip to hold said cage on said strip.12. An intermediate roller assembly, comprising:a strip having one facewhich includes at least one roller track that extends longitudinally ofsaid strip and retaining surfaces on sides thereof; a plurality ofroller elements in rolling contact with said at least one track; and acage comprising a plate that generally extends in a plane that issubstantially parallel to said at least one roller track, a plurality ofcells in said plate and in which said roller elements are respectivelyreceived, and lateral tabs that extend from longitudinal edges of saidplate and cooperate with said retaining surfaces of said strip such thatsaid lateral tabs hold said plate and said plurality of roller elementson said strip, whereby said strip, said roller elements and said cageform an interconnected unitary assembly.
 13. The intermediate rollerelement of claim 12, wherein at least one of said cage and said stripfurther comprises a means for limiting displacement of said cage withrespect to said strip in the longitudinal rolling direction of saidroller elements in the longitudinal direction of said strip.
 14. Theintermediate roller element of claim 12, wherein said means for limitingdisplacement of said cage with respect to said strip in the longitudinalrolling direction of said roller elements comprises a stop piece formedon said at least one track that projects outwardly of said at least onetrack and divides said at least one track into two tracks, each of saidtracks having at least one said roller element thereon.
 15. Anintermediate roller assembly, comprising:a strip having one face whichincludes at least one roller track that extends longitudinally of saidstrip and retaining surfaces on sides thereof; a plurality of rollerelements in rolling contact with said at least one track; a cagecomprising a plate theft extends in a plane that is substantiallyparallel to said at least one roller track, a plurality of cells in saidplate and in which said roller elements are respectively received, andlateral tabs that extend from longitudinal edges of said plate andcooperate with said retaining surfaces of said strip such that saidlateral tabs hold said plate and said plurality of roller elements onsaid strip, whereby said strip, said roller elements and said cage forman interconnected unitary assembly; and wherein said strip tapers awayfrom said track at said retaining surfaces, said lateral tabs extendfrom a position adjacent to said track to said retaining surfaces, andsaid lateral tabs extend inwardly toward said retaining surfaces atdistal ends thereof so as to be capable of holding said cage on saidstrip.
 16. The intermediate roller assembly of claim 15, wherein saidlateral tabs are elastically deformable.
 17. An intermediate rollerassembly, comprising:a strip having one face which includes at least oneroller track that extends longitudinally of said strip and retainingsurfaces on sides thereof; a plurality of roller elements in rollingcontact with said at least one track; a cage comprising a plate thatextends in a plane that is substantially parallel to said at least oneroller track, a plurality of cells in said plate and in which saidroller elements are respectively received, and lateral tabs that extendfrom longitudinal edges of said plate and cooperate with said retainingsurfaces of said strip such that said lateral tabs hold said plate andsaid plurality of roller elements on said strip, whereby said strip,said roller elements and said cage form an interconnected unitaryassembly; wherein at least one of said cage and said strip furthercomprises a means for limiting displacement of said cage with respect tosaid strip in the longitudinal rolling direction of said roller elementsin the longitudinal direction of said strip; and wherein said means forlimiting displacement of said cage with respect to said strip in thelongitudinal rolling direction of said roller elements comprises atleast one fixed stop piece formed on said strip and at least one stopsurface on said cage, said fixed stop piece being capable of interactingwith said at least one stop surface.
 18. The intermediate roller elementof claim 17, wherein said at least one fixed stop piece comprises atleast one fixed projecting stop piece projecting from one of saidlateral faces of said strip, and said at least one stop surface on saidcage comprises two stop-piece surfaces forming longitudinal end edges ofa window formed in one of said lateral tabs of said cage.
 19. Theintermediate roller element of claim 17, wherein said strip has oppositelongitudinal ends on one of said lateral faces thereof, said at leastone fixed stop piece comprises stop pieces located at said oppositelongitudinal ends of said lateral face, and one of said lateral tabs ofsaid cage is received with a clearance between said stop pieces, said atleast one stop surface being formed on the one of said lateral tabs ofsaid cage.